XP Home - Virtual memory issue

Whenever I attempt to connect to an online game of Unreal Tournament 2003 and the master server is queried to list the available servers, my PC crashes back to the desktop with a message that my virtual memory is low and I should free up more space on the hardrive.

I have an AMD XP1900 PC with 1024mb ram and more than 20gb free space on my hard drive. Os is XP Home.

This does not happen with any other application and if I run the same game over my network, no problem.

Is there any way that I can increase virtual memory? If not, any ideas?